Field of the Invention
The present invention relates to a coil component and a manufacturing method of the coil component, and particularly to a coil component that uses a drum core and a manufacturing method thereof.
Description of Related Art
In recent years, electronic components that are used in information terminal devices such as smartphones have been strongly required to be smaller in size and lower in height. Therefore, as for coil components such as pulse transformers, surface-mount coil components that use drum cores instead of toroidal cores have been frequently used. For example, Japanese Patent Application Laid-Open No. 2012-119568 discloses a step-up transformer of a surface-mount type that uses a drum core.
The drum core of the pulse transformer disclosed in Japanese Patent Application Laid-Open No. 2014-199906 includes a flange portion having amount surface and an outer side. As shown in FIG. 2 of Japanese Patent Application Laid-Open No. 2014-199906, the mount surface of the flange portion has grooves and ridges at its mount surface. Wires are connected, at one end, to the ridges. The outer side of the flange portion is flat, and no terminal electrodes are formed on the outer side. When the pulse transformer disclosed in Japanese Patent Application Laid-Open No. 2014-199906 is mounted on a printed circuit board, solder will fill the gap between the lands formed on the printed circuit board and the ridges of the flange portion. By contrast, no solder fillets will be formed outside the flange, because no terminal electrodes are formed on the outer side of the flange portion.
In recent years, it is desired that coil components for use in vehicles, in particular, should have higher reliability than before. To meet this demand, it would important to form solder fillets when the coil component is mounted. In order to form solder fillets, terminal electrodes must be formed on the outer side of the flange portion. However, the step of forming the terminal electrodes will be complicated if the outer side of the flange portion is flat as in the drum core described in Japanese Patent Application Laid-Open No. 2014-199906.